A powerful 7.0 magnitude earthquake hit southern Japan early Saturday, the U.S. Geological Survey said, a day after another powerful tremor killed at least nine people in the same area.

The quake hit Kumamoto prefecture of the Kyushu main island at 1:25 a.m., the USGS said.

The Japan Meteorological Agency, which put the magnitude at 7.1, initially issued a tsunami warning for the western coast of Kyushu island, where hundreds were injured in a quake late Thursday, but later lifted it.

Several aftershocks rattled the area after Saturday's earthquake, the Japanese Meteorological Agency said.

NHK said there were multiple reports of fresh injuries and that a bridge in Kumamoto city had collapsed, though that could not be immediately confirmed.

There were several reports of people being trapped under debris at various locations, and the broadcaster showed images of rescue workers removing debris from atop a collapsed house in an apparent search for anyone trapped underneath.

Other footage showed residents gathering in a park and also scenes from the NHK bureau in Kumamoto city immediately after the quake, with objects falling off desks and shelves.

A 6.5-magnitude quake that struck late Thursday killed nine people and injured nearly 900.

According to the USGS, aftershocks are smaller earthquakes that occur after a larger event, the mainshock. If an aftershock occurs that's larger than the earlier quake, the larger earthquake is considered the mainshock -- and the earlier quakes are called foreshocks.

Avalanches, in which snow, ice, soil and rocks break loose and move rapidly down a mountainside, are a scary and and potentially lethal natural hazard.
Read on to learn about some of the spots on the planet where deadly avalanches have occurred.

World War I was deadly enough without avalanches. Nevertheless, a series of December 1916 slides, starting with one on Mount Marmolada that dropped 200,000 tons of ice and snow on a military barracks, were as deadly as many battles, killing thousands of troops from Italy and Austria-Hungary.

This is the site of what probably was the worst avalanche in history, a May 1970 event triggered by a 7.8 earthquake. Snow and ice came sliding down the mountain at 175 miles per hour speed, totally burying the town of Yungay in snow and ice and taking the lives of an estimated 20,000 people.